The present invention relates to a filtering apparatus and, more particularly, to a filtering apparatus in which a filter, which is wound on a filtration drum rotatably driven in order to filter and separate a liquid and solids mixedly contained in soil water after the water is used in, e.g., various types of industrial machines so that the liquid or solids can be recycled, is made exchangeable.
Conventionally, many filtering apparatuses are proposed that separate cutting oil, which contains chips after being used for metal machining, into chips and cutting oil, thus obtaining recyclable cutting oil (to be referred to as purified cutting oil hereinafter).
In such a filtering apparatus, a filter is detachably wound on opening portions formed in the outer circumferential surface of a filtration drum which is rotatably driven. The filter is exchanged when a predetermined period of operation time lapses or it is broken.
Description will be made with reference to the accompanying drawings. FIG. 5 is an outer appearance perspective view showing how to exchange a filter.
Referring to FIG. 5, a plurality of opening portions 202 are formed in the outer circumferential surface of a filtration drum 201 which is supported to rotate about a main shaft 204. Stud bolts 205 are welded at a constant interval on the filtration drum 201 in the radial direction in order to wind and fix a filter 220 on the opening portions 202.
Mounting hole portions 220c are formed in the filter 220 at portions where the stud bolts 205 on the filtration drum 201 sides are inserted, and the filter 220 has a filter portion 220b having a predetermined mesh size. In order to wind and fix the filter 220 having the above arrangement on the filtration drum 201, the mounting hole portions 220c are respectively fitted on the stud bolts 205, and the entire filter 220 is wound on the filtration drum 201. Thereafter, metal fixtures 221 which are bent in advance to match the arc of the outer circumference of the filtration drum 201 are placed on the filtration drum 201 such that their through hole portions 221b formed at a pitch corresponding to the pitch of the stud bolts 205 are set as shown in FIG. 5. Finally, nuts 31 are threadably engaged and fixed on the stud bolts 205.
In the above manner, the filter 220 is fixed near the edge portions of the outer circumferential surface of the filtration drum 201. As a result, the filter wound on the filtration drum 201 is prevented from moving toward the center in the thrust direction of the rotating shaft of filtration drum 201, and the filter 220 is held in liquid-tightness.
As described above, fixing of the filter 220 requires at least four different works:
(a) To fit the mounting hole portions 220c on all of the respective stud bolts 205; PA1 (b) To wind the entire portion of the filter 220; PA1 (c) To set the large number of metal fixtures 221; and PA1 (d) To threadably engage and fix the nuts 31 with the respective stud bolts 205.
The total time of the filter exchange work after the filtration drum is removed from the filtering apparatus is about 30 minutes when it is done by a person skilled in the art.
If the filter exchange work requires much time in this manner, the down time of the entire portion of other machine facilities where the filtering apparatus is arranged suffers directly. Therefore, a maximum possible reduction in the filter exchange time is sought.
Since a large number of stud bolts must be arranged in the radial direction standing upright on the filtration drum, an increase in cost is inevitable. Similarly, it is not preferable to form a large number of mounting hole portions in the filter which is an expendable supply. It is difficult to bend the metal fixtures 221 into an arc that matches the arc of the outer circumference of the filtration drum. However, if the metal fixtures 221 are not bent appropriately, a gap may form on the filter mounting surface, and liquid-tightness cannot be maintained. Since the filter is mounted such that no force is generated at all in the thrust direction of the rotating shaft of the filtration drum, the filter may sometimes loosen in the thrust direction of the rotating shaft.